<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container {
            width: 600px;
            height: 400px;
            background-color: pink;
            border: 1px solid #000;
            margin: 0 auto;
            display: flex;
            align-items: flex-end;
        }
        .box {
            font-size: 50px;
            height: 100px;
            color: #fff;
            line-height: 100px;
            text-align: center;
        }
        .box1 {
            width: 300px;
            background-color: green;
            /* order调节顺序 */
            /* order: 3; */
            /* 不要缩小 */
            /* flex-shrink: 0; */
            /* 占据空间 */
            /* flex-basis: 400px; */
            /* 简写 */
            flex: 0 0 400px;

        }
        .box2 {
            width: 200px;
            background-color: skyblue;
            /* order: 2; */
            /* 放大 */
            /* flex-grow: 1; */
            /* 缩小比例 */
            /* flex-shrink: 1; */
            flex: 1 1 auto;
            /* 居中对齐 */
            align-self: center;
        }
        .box3 {
            width: 400px;
            background-color: yellowgreen;
            /* order: 1; */
            /* 放大 */
            /* flex-grow: 1; */
            /* flex-shrink: 2; */
            flex: 1 2 auto;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="box box1">1</div>
        <div class="box box2">2</div>
        <div class="box box3">3</div>
    </div>
</body>
</html>